[8p-F212-1~14] 9.1 Dielectrics, ferroelectrics

2:30 PM - 2:45 PM JST(5:30 AM - 5:45 AM UTC)Presentation by Applicant for JSAP Young Scientists Presentation Award

[8p-F212-5] First-principles calculation of temperature dependence of dielectric constant at the anharmonic phonon level

〇Tasuku Watanuki¹, Keisuke Ide¹, Takayoshi Katase¹, Hideo Hosono¹, Toshio Kamiya¹ (1.MDXES, Science Tokyo)

Keywords:

dielectric constants,phonons

We developed first-principles methods to calculate temperature dependences of dielectric constants using anharmonic phonon calculations. The methods were applied to NaCl and cubic BaTiO₃, confirming that their experimental temperature dependences were successfully reproduced. In NaCl, the dominant contribution to the temperature dependence is thermal expansion at the quasi-harmonic approximation level. On the other hand, for BaTiO₃, anharmonic effects must be considered, so self-consistent phonon approach qualitatively reproduces the experimental behavior, which follows Curie-Weiss law. The present methods were applied to a series of new ferroelectric candidate materials identified by first-principles high-throughput screening. However, the present results also suggest that both the effects, lattice expansion and lattice anharmonicity should be incorporated for general-purpose, high accuracy prediction, which we will talk at the conference.